1. Field of the Invention
The present invention relates to thermal therapy devices. More particularly the invention relates to thermal therapy devices comprising a plurality of hydrated hydrophillic absorbers and a means for preventing clumping of the absorbers over extended cycles of freezing/melting.
2. Prior Art
Thermal therapy is a conventional method of rehabilitating injuries such as bruises and sprains to bone, muscle, ligaments, tendons, and skin. Heat therapy is often employed to loosen joint tissue while cold therapy is preferred for reducing swelling, pain, and to promote healing. Cold therapy is also known to be beneficial after surgery additionally for reducing swelling and promoting healing. By lowering the temperature of the injured tissue, the metabolic rate is reduced which allows the tissue to survive and recover during the period following the injury.
A conventional cold therapy method is simply to apply ice to the affected area. This can include wrapping bags of ice around the injury, however is not preferred due to the lack of temperature control and possible damage (frost-bite) to the skin and surrounding tissue. As a result, cold therapy can be applied with the provision of a re-freezable device which does exceed the cooling temperature and time recommended by medical professionals.
Prior art has made many attempts to provide thermal therapy devices which can be employed for many freezing/melting cycles and therefore provide extend use by the user. U.S. Pat. No. 5,800,491 to Kolen et. al., herein incorporated in its entirety by reference, teaches a thermal therapy device employing a mixture of discrete hydrophilic absorbers and a hydrating liquid mixture comprising a substantial amount of water which freezes under normal freezer conditions (32° F. to −20° F.) and increases the heat capacity of the therapy device.
In use, when freezing the device to Kolen, the water retained within the hydrophilic absorbers migrates out and freezes in discrete white ice crystals and, when thawed, melted water is reabsorbed by the hydrophilic absorbers. The water conventionally solidifies around the absorbers of which it migrates out, individual hydrophillic absorbers remain in discrete form due to the control of the water flow in and out of the hydrophilic absorbers. The device includes a flexible container with an air passage having an air permeable membrane which allows air to pass in and out of the container as the device expands/contracts during freezing/thawing cycles, respectively. There are also included a plurality of non-absorbing beads which are employed as a means for increasing the thermal resistance through the device. The provisions and features of the device allow the device to maintain substantial pliability in both the thawed and frozen states within a conventional operating period of 2 to 40 cycles. Pliability is desired since the device must conform to the curves and bends of the human body during application.
The device to Kolen is considered a great advance in the art, however, experimentation has shown that the device fails to maintain its pliable and flexible characteristics after extended cycles of freezing/thawing past the conventional operating period. This makes the device less desirable to users after prolonged operative employment. This is most commonly attributed to the process of ‘clumping’ of the discrete absorbers, when ice crystals forming on at least two adjacent absorbers bond or adhere together over prolonged and repeated freezing/thawing cycles which rigidizes the flexible container containing the absorbers. Despite the assertions in the disclosure to Kolen that the discrete absorbers retain their discrete forms over time, clumping has been shown to occur during the freezing cycle after prolonged and repeated use of the device; as the water migrates out and solidifies around the discrete absorbers, adjacent discrete ice/absorber formations will tend to bond together, creating clumps. In addition, the absorbers will gradually break down into ever small pieces with each usage, this also increases the tendency to clump.
Those skilled in the art could easily ascertain that repeated cycles of freezing/melting will cause the absorber material to degrade and wear. Therefor the ability to control water flow out of the hydrophilic absorbers during the freezing process is substantially diminished. As such, the once discrete formations will bond together and become large formations (clumps) which are rigid and not easily broken apart therefor inhibiting the pliable characteristic of the device. At this point the user will often discard the device and opt for other means for cold therapy.
Still further, an additional downfall noted about the device is the manner in which the device is frozen and/or stored by the user. The device to Kolen is intended to be placed within a users freezer, wherein as noted above the water migrates out of the discrete absorbers then solidifies in a discrete formation. During this process, the solidification of the liquid water into ice will increase the volume of the flexible container of which the absorbers and fluid mixture are contained within. The air membrane allows excess air escape the container in order to prevent a rupture of the container, however, there is still a substantial increase in the overall volume of the device. The device must be able to expand without resistance to insure that the ice forms in discrete formations around the absorbers. In the event that the device cannot freely expand, such as in a crowded freezer, the discrete ice/absorber formations will again tend to bond together into rigid clumps.
As such, there is a continuing unmet need for a thermal therapy device having hydrophillic absorbers and having means for preventing clumping of the discrete absorbers during freezing cycles. Such means for preventing clumping should preferably be providing by an added particulate which provides a physical separation means between at least two adjacent absorbers during the freezing cycle. Such a thermal therapy device can then be employed over extended cycles of freezing/melting without the occurrence of adjacent ice/absorber formations bonding (clumping) together. Such a device should provide a means for physical separation which is added to a mixture of hydrophillic absorbers and liquid mixture, which acts as a barrier to prevent discrete ice/absorber formations from clumping together.
Further, such a device should be provided to the user in a kit additionally comprising a rigid storage container component which can house the device during the freezing process and therefor allow the device to uninterruptedly expand to a predetermined volume. Such a container component can also include a means for visually ascertaining that the freezing cycle of the device is completed.
The forgoing examples of related art and limitation related therewith are intended to be illustrative and not exclusive, and they do not imply any limitations on the invention described and claimed herein. Various limitations of the related art will become apparent to those skilled in the art upon a reading and understanding of the specification below and the accompanying drawings.